1. Field
Exemplary embodiments of the present invention relate to a metal wire etchant and a method of forming a metal wire using the same.
2. Description of the Background
In general, a thin film transistor (TFT) array panel may be used as a circuit board for independently driving each pixel in a liquid crystal display, an organic electroluminescence (EL) display device, or the like. The thin film transistor array panel may be formed of a gate wire transferring a scanning signal and a data wire transferring an image signal, and may be constituted by a thin film transistor connected to the gate wire and the data wire, a pixel electrode connected to the thin film transistor, and the like.
The thin film transistor may be constituted by a gate electrode that is a portion of the gate wire, a semiconductor layer forming a channel, and a source electrode and a drain electrode that are portions of the data wire. The thin film transistor may be a switching element either transferring a data voltage transferred through the data wire to the pixel electrode or interrupting the data voltage according to the gate signal transferred through the gate wire.
When the thin film transistor is manufactured, first, a metal layer is laminated on a substrate with a wire material for gate or source/drain electrodes, and an etching process of implementing a desired line path of an electric circuit by corroding the metal layer by gas or a solution having a corrosion property follows.
A circuit line becomes thinner as the circuit is reduced in size and integrated, thereby providing a relative increase in electrical resistance. Therefore, copper is receiving attention as a wire material having low resistance as a possible replacement for chromium, molybdenum, aluminum, and an alloy thereof, which are mainly used as known circuit line materials.
However, because copper has relatively poor adherence to a glass substrate or a silicon insulating layer, it is difficult to use as a single layer, and accordingly, a multilayer employing copper and a metal layer having excellent adherence to the glass substrate or the silicon insulating layer as a lower layer may be used.
A peroxide-based etchant may be used to etch the multilayer, and because the peroxide-based etchant rapidly decomposes into water and oxygen by promoting decomposition of peroxides, if a metal ion has at least a predetermined concentration, heat emission and a rapid composition change may occur, thereby reducing stability. A method of adding a peroxide stabilizer has been used in order to solve the problems of hydrogen peroxides, but the high price of the stabilizer increases cost.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.